2012 AGU Chapman Conference on Remote Sensing of the ...

hydrologists, was initially assigned to tier 3, but since hasbeen assigned higher priority. In addition, the GlobalPrecipitation Measurement mission (GPM), which was onthe verge of cancellation at the time the Decadal Review wasinitiated, is now on track for launch in 2014. However, all hasnot gone smoothly in the five years since ESAS. Two socalled“foundational missions” (missions already indevelopment at the time of ESAS) were lost due to launchfailures – OCO (the Orbital Carbon Observatory) in early2009 and Glory (solar irradiance and aerosol observations)in 2011. Costs of the four tier 1 missions have escalatedrapidly, to the point that two of the four (DESDYNI –interferometric SAR and lidar for surface deformation andrelative surface process research) and CLAREO (solarirradiance) have been placed on indefinite hold. In addition,budget cuts make it almost certain that launch dates for theremaining tier 1 and tier 2 missions which nominally are “ontrack” will be extended, and the likelihood of launch of anytier 3 missions within the decade is essentially nil. Againstthis backdrop, I evaluate the outlook for the next generationof hydrology and water cycle missions, including the needand opportunity for international collaboration, and theopportunities for alternative (e.g. suborbital) remote sensingplatforms and their relevance to hydrologic problems.Lievens, HansAssimilation of SMOS data into a coupled landsurface and radiative transfer model for improvingsurface water managementPauwels, Valentijn R. 1 ; Lievens, Hans 1 ; Verhoest, Niko E. 1 ; DeLannoy, Gabrielle 1 ; Plaza Guingla, Douglas 1 ; van den Berg,Martinus J. 1 ; Kerr, Yann 2 ; Al Bitar, Ahmad 2 ; Merlin, Olivier 2 ;Cabot, Francois 2 ; Gascoin, Simon 2 ; Wood, Eric 3 ; Pan, Ming 3 ;Sahoo, Alok 3 ; Walker, Jeffrey 4 ; Dumedah, Gift 4 ; Drusch,Matthias 51. Laboratory of Hydrology and Water Management, GhentUniversity, Ghent, Belgium2. Centre d’Etudes Spatiales de la Biospehère, Toulouse,France3. Land Surface Hydrology Group, Princeton University,Princeton, NJ, USA4. Department of Civil Engineering, Monash University,Melbourne, VIC, Australia5. European Space Agency, Noordwijk, NetherlandsThe Soil Moisture and Ocean Salinity (SMOS) satellitemission is routinely providing novel accurate data with ahigh acquisition frequency at the global scale. However, theintegration of low resolution SMOS observations into finerresolution land surface models poses significant challenges,through which the potential of the satellite mission foroperational hydrology is at present poorly understood.Therefore, this study aims at developing a robust end-to-endmethodology that allows for the assimilation of SMOS data(either brightness temperature or soil moisture) into landsurface models and for assessing the usefulness of SMOSdata with respect to flood forecast. The assimilation systemis being set up for the Variable Infiltration Capacity (VIC)land surface model, coupled to a river routing scheme. TheVIC model will be run over two large river basins, the UpperMississippi Basin in central USA, and the Murray DarlingBasin in Eastern Australia, both of which are characterizedby a low contamination with radio frequency interference(RFI). A radiative transfer model, the Community MicrowaveEmission Model (CMEM), is being coupled to VIC in orderto assimilate the top of atmosphere (TOA) brightnesstemperatures from SMOS over both river basins, in additionto derived soil moisture. The data assimilation system to beused is the Ensemble Kalman filter. Finally, differentdisaggregation strategies will be explored to analyze theoptimal way for integrating low resolution SMOSobservations into higher resolution land surface models.http://www.hydro-smos.be/Lievens, HansSoil moisture retrieval from SAR over bare soil andwheat fields based on Water Cloud modeling, theIEM and effective roughness parametersLievens, Hans 1 ; Verhoest, Niko 11. Laboratory of Hydrology and Water Management, GhentUniversity, Ghent, BelgiumThe retrieval of the top surface soil moisture contentfrom Synthetic Aperture Radar (SAR) has been extensivelystudied during the past decades; nevertheless, it remains achallenging task. Particularly for bare soil fields, theparameterization of the surface roughness is veryambiguous. Field measurements of roughness parameters,such as the surface root mean square (RMS) height, show tobe highly variable even within one agricultural field, andmoreover strongly depend on the measurement techniqueapplied. Furthermore, the soil moisture retrieval ofagricultural fields is often hampered by varying vegetationeffects on the backscattered signal along the growing season.This study analyses the potential and limits of a soilmoisture retrieval methodology which is based on the IEMand calibrated or effective roughness parameters. Theretrieval technique is applied to a large number of bare soilagricultural fields in Flevoland, The Netherlands, over whicha series of C-band RADARSAT-2 HH- and VV-polarizedacquisitions have been collected in the frame of the AgriSAR2009 campaign, organized by the European Space Agency(ESA). The retrieval accuracy is found to be around 4 vol%,with slightly better performance for HH than VVpolarization. Furthermore, it is analyzed whether the soilmoisture retrieval methodology can be prolongedthroughout the growing season of wheat. Therefore, theretrieval technique developed for bare soil fields is extendedthrough including a vegetation backscatter model, i.e., thesemi-empirical Water Cloud Model (WCM). A number ofbulk vegetation parameters, involving LAI, VWC, and LWAI,are investigated with regard to the modeling of wheatcanopy and the retrieval of the underlying soil moisturecontent. For a series of L-band E-SAR acquisitions duringAgriSAR 2006, the use of LAI yields the highest soil moistureretrieval accuracy, i.e., RMSE = 5.5 vol%. These results91